Endodontic therapy - AbsoluteAstronomy.com

Endodontic therapy is a sequence of treatment for the pulp

Pulp (tooth)

The dental pulp is the part in the center of a tooth made up of living connective tissue and cells called odontoblasts.- Anatomy :Each person can have a total of up to 52 pulp organs, 32 in the permanent and 20 in the primary teeth....

of a tooth

Tooth

Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

which results in the elimination of infection and protection of the decontaminated tooth from future microbial invasion. This set of procedures is commonly referred to as a "root canal." Root canal

Root canal

A root canal is the space within the root of a tooth. It is part of a naturally occurring space within a tooth that consists of the pulp chamber , the main canal, and more intricate anatomical branches that may connect the root canals to each other or to the surface of the root.-Root canal anatomy:...

s and their associated pulp chamber are the physical hollows within a tooth that are naturally inhabited by nerve tissue, blood vessel

Blood vessel

The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

s and other cellular

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

entities. Endodontic therapy involves the removal of these structures, the subsequent cleaning, shaping, and decontamination of the hollows with tiny files and irrigating solutions, and the obturation (filling) of the decontaminated canals with an inert filling such as gutta percha and typically a eugenol-based cement

Zinc Oxide Eugenol

Zinc oxide eugenol is a material created by the combination of zinc oxide and eugenol contained in oil of cloves. An acid-base reaction takes place with the formation of zinc eugenolate chelate. The reaction is catalysed by water and is accelerated by the presence metal salts. ZOE can be used as...

.

After endodontic surgery the tooth will be "dead," and if an infection is spread at apex, root end surgery is required.

Although the procedure is relatively painless when done properly, the root canal remains a stereotypically fearsome dental operation, and, in the United States, a common response to an unpleasant proposal is, "I'd rather have a root canal."

Root canal treatment

In the situation that a tooth is considered so threatened (because of decay, cracking, etc.) that future infection is considered likely or inevitable, a pulpectomy, removal of the pulp tissue, is advisable to prevent such infection. Usually, some inflammation and/or infection is already present within or below the tooth. To cure the infection and save the tooth, the dentist drills into the pulp chamber and removes the infected pulp and then drills the nerve out of the root canal(s) with long needle-shaped drills. After this is done, the dentist fills each of the root canals and the chamber with an inert material and seals up the opening. This procedure is known as root canal therapy. With the removal of nerves and blood supply from the tooth, it is best that the tooth be fitted with a crown

Crown (dentistry)

A crown is a type of dental restoration which completely caps or encircles a tooth or dental implant. Crowns are often needed when a large cavity threatens the ongoing health of a tooth. They are typically bonded to the tooth using a dental cement. Crowns can be made from many materials, which...

which increases the prognosis of the tooth by six times.

The standard filling material is gutta-percha

Gutta-percha

Gutta-percha is a genus of tropical trees native to Southeast Asia and northern Australasia, from Taiwan south to the Malay Peninsula and east to the Solomon Islands. The same term is used to refer to an inelastic natural latex produced from the sap of these trees, particularly from the species...

, a natural non-elastic latex from the sap of the percha (Palaquium gutta) tree. The standard endodontic technique involves inserting a gutta-percha cone (a "point") into the cleaned-out root canal along with cement and a sealer. Another technique uses melted or heat-softened gutta-percha which is then injected or pressed into the root canal passage(s). However, gutta-percha shrinks as it cools, so thermal techniques can be unreliable; sometimes a combination of techniques is used. Gutta-percha is radiopaque

Radiodensity

Radiodensity refers to the relative inability of electromagnetic radiation, particularly X-rays, to pass through a particular material. Radiolucency indicates greater transparency or "transradiancy" to X-ray photons...

, allowing verification afterwards that the root canal passages have been completely filled in, without voids.

An alternative filling material was invented in the early 1950s by Angelo Sargenti. It has undergone several formulations over the years (N2, N2 Universal, RC-2B, RC-2B White), but all contain paraformaldehyde. The paraformaldehyde, when placed into the root canal, forms formaldehyde, which penetrates and sterilizes the passage. The formaldehyde is then theoretically transformed to harmless water and carbon dioxide. If the Sargenti paste is confined to the tooth root, the outcome is similar to a root canal done with gutta percha. Unfortunately, in rare cases, the paste can be forced past the root tip into the surrounding bone. If this happens, the formaldehyde can cause serious and painful permanent damage to the bone. Therefore, the American Association of Endodontists considers the Sargenti technique unsafe and substandard care. In 1991 the ADA Council on Dental Therapeutics resolved that the treatment was "not recommended", and it is not taught in any American dental school. The Sargenti technique has its advocates, however, who believe N2 to be less expensive and at least as safe as gutta-percha.

For some patients, root canal therapy is one of the most feared dental procedures, perhaps because of a painful abscess that necessitated the root canal procedure. However, dental professionals assert that modern root canal treatment is relatively painless because the pain can be controlled with a local anesthetic during the procedure and pain control medication can be used before and/or after treatment assuming that the dentist takes the time to administer one. However, in some cases it may be very difficult to achieve pain control before performing a root canal. For example, if a patient has an abscessed tooth

Tooth abscess

A tooth abscess or root abscess is pus enclosed in the tissues of the jaw bone at the apex of an infected tooth's root. Usually the abscess originates from a bacterial infection that has accumulated in the soft, often dead, pulp of the tooth. This can be caused by untreated tooth decay, cracked...

, with a swollen area or "fluid-filled gum blister" next to the tooth, the pus in the abscess may contain acids that inactivate any anesthetic injected around the tooth. In this case, the dentist may drain the abscess by cutting it to let the pus drain out. Releasing the pus releases pressure built up around the tooth; this pressure causes the pain. The dentist then prescribes a week of antibiotics such as penicillin

Penicillin

Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....

, which will reduce the infection and pus, making it easier to anesthetize the tooth when the patient returns one week later. The dentist could also open up the tooth and let the pus drain through the tooth, and could leave the tooth open for a few days to help relieve pressure.
At this first visit, the dentist must ensure that the patient is not biting into the tooth, which could also trigger pain. Sometimes the dentist performs preliminary treatment of the tooth by removing all of the infected pulp of the tooth and applying a dressing and temporary filling to the tooth. This is called a pulpectomy. The dentist may also remove just the coronal portion of the dental pulp, which contains 90% of the nerve tissue, and leave intact the pulp in the canals. This procedure, called a "pulpotomy", tends to essentially eliminate all the pain. A pulpotomy

Pulpotomy

A healthy tooth has a space inside it called the "pulp space" which is filled with soft tissues - nerves, blood vessels and pink connective tissue. It looks kind of like what you'd see underneath your skin if you grazed it...

may be a relatively definitive treatment for infected primary teeth

Deciduous teeth

Deciduous teeth, otherwise known as reborner teeth, baby teeth, temporary teeth and primary teeth, are the first set of teeth in the growth development of humans and many other mammals. In some Asian countries they are referred to as fall teeth as they will eventually fall out, while in almost all...

. The pulpectomy and pulpotomy procedures eliminate almost all pain until the follow-up visit for finishing the root canal. But if the pain returns, it means any of three things: the patient is biting into the tooth, there is still a significant amount of sensitive nerve material left in the tooth, or there is still more pus building up inside and around the infected tooth; all of these cause pain.

After removing as much of the internal pulp as possible, the root canals can be temporarily filled with calcium hydroxide

Calcium hydroxide

Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca2. It is a colourless crystal or white powder and is obtained when calcium oxide is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or...

paste. This strong alkaline base is left in for a week or more to disinfect and reduce inflammation in surrounding tissue. Ibuprofen

Ibuprofen

Ibuprofen is a nonsteroidal anti-inflammatory drug used for relief of symptoms of arthritis, fever, as an analgesic , especially where there is an inflammatory component, and dysmenorrhea....

taken orally is commonly used before and/or after these procedures to reduce inflammation.
The following substances are used as root canal irrigants during the root canal procedure:

5.25% sodium hypochlorite (NaOCl)
6% sodium hypochlorite with surface modifiers for better flow into nooks and crannies
2% chlorhexidine gluconate
Chlorhexidine gluconate
Chlorhexidine is a chemical antiseptic. It is effective on both Gram-positive and Gram-negative bacteria, although it is less effective with some Gram-negative bacteria. It has both bactericidal and bacteriostatic mechanisms of action, the mechanism of action being membrane disruption, not ATPase...

(Perioxidina Plus-2)
0.2% chlorhexidine gluconate plus 0.2% cetrimide (Cetrexidin)
17% ethylenediaminetetraacetic acid (EDTA)
Framycetin
Framycetin
Framycetin is an antibiotic of the aminoglycoside class similar to neomycin. Like neomycin, it has poor systemic absorption. It is used in topical preparations for infections of the skin, nose, ears, and eyes, often in combination with other antibacterial drugs and corticosteroids...

sulfate (Septomixine)
Biopure MTAD Mixture of citric acid, Docycline, and Tween-80 (detergent) by Dentsply USA (MTAD)

After receiving a root canal, the tooth should be protected with a crown that covers the cusps of the tooth. Otherwise, over the years the tooth will almost certainly fracture, since root canals remove tooth structure from the tooth and undermine the tooth's structural integrity. Also, root canal teeth tend to be more brittle than teeth not treated with a root canal. This is commonly because the blood supply to the tooth, which nourishes and hydrates the tooth structure, is removed during the root canal procedure, leaving the tooth without a source of moisture replenishment. Placement of a crown or cusp-protecting cast gold covering is recommended also because these have the best ability to seal the root canaled tooth. If the tooth is not perfectly sealed, the root canal may leak, causing eventual failure of the root canal. Also, many people believe once a tooth has had a root canal treatment it cannot get decay. This is not true. A tooth with a root canal treatment still has the ability to decay, and without proper home care and an adequate fluoride

Fluoride

Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...

source the tooth structure can become severely decayed (often without the patient's knowledge since the nerve has been removed, leaving the tooth without any pain perception). Thus, non-restorable carious

Dental caries

Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...

destruction is the main reason for extraction of teeth after root canal therapy, with up to two-thirds of these extractions. Therefore it is very important to have regular X-rays taken of the root canal to ensure that the tooth is not having any problems that the patient would not be aware of.
The procedure is often complicated, depending on circumstances, and may involve multiple visits over a period of weeks. The cost is typically high.

Innovation

In the last ten to twenty years, there have been great innovations in the art and science of root canal therapy. Dentists now must be educated on the current concepts in order to optimally perform a root canal. Root canal therapy has become more automated and can be performed faster, thanks to advances in automated mechanical instrumentation of teeth and more advanced root canal filling methods. Most root canal procedures are done in one dental visit, lasting around 1–2 hours. Dentists also possess newer technologies that allow more efficient, scientific measurements to be taken of the dimensions of the root canal that must be filled. Many dentists use dental loupe

Loupe

A loupe is a simple, small magnification device used to see small details more closely. Unlike a magnifying glass, a loupe does not have an attached handle, and its focusing lens are contained in an opaque cylinder or cone. Loupes are also called hand lenses .- Optics :Three basic types of loupes...

s to perform root canals, and the consensus is that root canals performed using loupes or other forms of magnification are more likely to succeed than those performed without them. Although general dentists are becoming versed in these advanced technologies, they are still more likely to be used by specialist root canal doctors (known as endodontists).

Laser root canal procedures are a controversial innovation. Lasers may be fast but have not been shown to thoroughly disinfect the whole tooth, and may cause damage.

Procedural accidents

Sometimes a tool can break while it is in the tooth. If the tip of a spiral metal file used by the doctor breaks off during the procedure, it is usually left behind and not extracted, leaving the patient with a small amount of retained metal. The occurrence of this event is proportional to the narrowness, curvature, length, calcification presence and number of roots on the tooth being treated. Complications resulting from retained metal are not well studied, but the occurrence of tool breakage is well documented.

Success and prognosis

Root canal treatments can fail. Patients should be educated on some of the reasons why root canals may fail. They may fail if the dentist does not find, clean and fill all of the root canals within a tooth. For example, on a top molar

Molar (tooth)

Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....

tooth, there is a more than 50% chance that the tooth has four canals instead of just three. But the fourth canal, often called a "mesio-buccal 2", tends to be very difficult to see and often requires special instruments and magnification in order to see it (most commonly found in first maxillary molars; studies have shown an average of 76% up to 96% of such teeth with the presence of an MB2 canal). So it may be missed, and this infected canal may cause a continued infection or "flare up" of the tooth. Any tooth may have more than one canal, which may be missed while performing the root canal. Sometimes the canal may be unusually shaped, making it impossible to fill it completely, so that some infected material is still left in the canal. Sometimes the canal filling does not extend deeply enough into the canal, or it does not fill the canal as much as it should. Sometimes a tooth root may be perforated while the root canal is being performed, making it difficult to fill the tooth. The hole may be filled with a material derived from natural cement called MTA

Mineral trioxide aggregate

Mineral trioxide aggregate is a material used to fill the root canals of teeth as part of root canal therapy. It has the ability to encourage hard tissue deposition similar to Calcium hydroxide effect. Also both have the same biological and histological properties.-Composition :It is composed of...

, although usually a specialist would perform this procedure. Fortunately, a specialist can often re-treat and definitively heal up these teeth, often years after the initial root canal procedure.

However, the survival or functionality of the endodontically-treated tooth is currently the emerging aspect of endodontic treatment outcome, rather than healing.
Recent studies indicate that substances commonly used to clean the interior of the tooth provide a low overall chance of succeeding in completely sterilizing a tooth internally. However, a properly restored tooth following root canal therapy yields long-term success rates near 97%. In this large scale Delta Dental Study of over 1.6 million patients who had root canal therapy, 97% had retained their teeth 8 years following the procedure, with most untoward events, such as re-treatment, apical

Apical

Apical, from the Latin apex meaning to be at the apex or tip, may refer to:*Apical , an anatomical term of location for features associated with the base of an organism or structure...

surgery or extraction, occurring during the first 3 years after the initial endodontic treatment. Endodontically treated teeth are prone to extraction mainly due to non-restorable carious

Dental caries

destruction and to a lesser extent to endodontic-related reasons such as endodontic failure, vertical root fracture (VRF), or perforation (procedural error).

Systemic issues

An infected tooth may endanger other parts of the body. People with special vulnerabilities, such as prosthetic joint replacement

Replacement joint

Replacement arthroplasty [from Greek arthron, joint, limb, articulate, + -plassein, to form, mould, forge, feign, make an image of], or joint replacement surgery, is a procedure of orthopedic surgery in which the arthritic or dysfunctional joint surface is replaced with an orthopaedic prosthesis...

or mitral valve prolapse

Mitral valve prolapse

Mitral valve prolapse is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. There are various types of MVP, broadly classified as classic and nonclassic. In its nonclassic form, MVP carries a low risk of...

, may need to take antibiotics to protect from infection spreading during dental procedures. Both endodontic therapy and tooth extraction can lead to subsequent jaw bone infection. The American Dental Association

American Dental Association

The American Dental Association is an American professional association established in 1859 which has more than 155,000 members. Based in Chicago, the ADA is the world's largest and oldest national dental association and promotes good oral health to the public while representing the dental...

(ADA) asserts that any risks can be adequately controlled.

In the early 1900s, several researchers theorized that bacteria from teeth which had necrotic pulps or which had received endodontic treatment could cause chronic or local infection in areas distant from the tooth through the transfer of bacteria through the bloodstream. This was called the "focal infection theory", and it led some dentists to advocate dental extraction. In the 1930s, this theory was discredited, but the theory was recently revived by a book entitled Root Canal Cover-Up Exposed which used the early discredited research, and further complicated by epidemiological studies which found correlations between periodontal disease and heart disease, strokes, and preterm births. Bacteremia

Bacteremia

Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....

(bacteria in the bloodstream) can be caused by dental procedures, particularly after dental extractions, but endodontically treated teeth alone do not cause bacteremia or systemic disease.

Alternatives to root canal treatment

The alternatives to root canal therapy are few. Extraction of the tooth is an option which can be followed with a tooth implant. Many people choose the alternative of "no treatment", but "no treatment" is often not a good alternative due to pain and/or infection.